The present invention relates to N-substituted pyrroles and their use in processes and compositions for altering the flavors and aromas of various consumable materials such as tobaccos, foodstuffs, perfumed articles, and the like, as well as novel N-substituted pyrroles and processes for producing them.
Because of the tremendous consumption of foods, tobaccos, and other materials, there has been an increasing interest in substances and methods for imparting flavors to such consumable materials. This interest has been stimulated not only because of the inadequate quantity of natural flavoring materials available, but perhaps even more importantly, because of the need for materials which can combine several nuances, will be more stable than natural materials, will blend better with other flavors or flavoring composition components, and will generally provide superior products.
Certain pyrrole derivatives are known, some of these have been suggested for use in flavoring foodstuffs. For uniformity herein, pyrroles contain a substituent on the ring nitrogen atom will be denominated as N-substituted pyrroles, and it will be understood that such materials can also be called 1-substituted pyrroles.
A variety of pyrroles is shown in U.S. Pat. No. 3,285,931, and they are stated to be useful as intermediates in the production of pyrrolidines for aging inhibitors and other uses. See also U.S. Pat. No. 2,770,628.
Canadian Pat. No. 868,720 shows treating tobacco with (2-pyrryl) ketones and aldehydes for the purpose of affecting the smoke flavor. N-methyl- and N-furfurylpyrrole and "higher pyrroles" are said to be present in coffee aroma, and a mixture is prepared to contain the first two N-pyrroles in U.S. Pat. No. 1,696,419. U.K. patent specification No. 1,156,482 shows a variety of N-substituted pyrroles used in foodstuffs.
Gianturco et al., Tetrahedron 20, 2951 (1964) discuss the presence of furanic and pyrrolic compounds in coffee. Stoll et al., Helvetica Chimica Acta, 50 (2), 628 (1967) shows N-substituted pyrroles in coffee aroma. Various N-substituted pyrroles are also shown in Ilomets et al., Chem. Abstr. 1964, 10629g; Kutscher et al., Chem. Ber. 99 (11), 3712 (1966); Buu-Hoi et al., Chem. Abstr. 41, 5976e; U.K. patent specification No. 1,161,638; Buu-Hoi et al., J. Chem. Soc. 1961, 4836; Mannschreck et al., Tetrahedron Letters 1963 (29), 2003; Gross et al., Chem. Ber. 95, 2270; Wolthuis et al., J. Org. Chem. 31(6), 2009; Hazlewood et al., Chem. Abstr. 32, 1965; Kaluza et al., J. Gas Chromat. 5(11), 562; and U.S. Pat. No. 2,859,833.
U.S. Pat. No. 2,492,414 shows N-methylolpyrrole and U.S. Pat. No. 2,766,145 shows derivatives of hydroxypyrrole used in tobacco to release an acid. Neurath, Beitrage zur Tabakforschung, Band 5, Heft 3, shows 2-(2-pyridyl) pyrroles in tobacco flavor. U.S. Pat. No. 3,458,515 deals with certain nitrogen heterocyclic-substituted pyrroles.